The Chargers will begin training camp next week without a long-time veteran defensive end.

Luis Castillo has been released, sources said Thursday, in a move that was discussed for weeks between the two sides. The 2005 first-round draft pick, who declined an interview request, will now consider his career options.

It is expected that Castillo, 28, could attempt to catch on elsewhere, perhaps with a team that offers more chance for playing time.

The Chargers have steadily added young pieces at the end position, investing draft picks in Corey Liuget, Vaughn Martin and Kendall Reyes since 2009. Castillo wasn't considered a lock for a roster spot out of training camp.

In light of recurring back issues that continue to trouble him, sources close to Castillo said he is weighing whether to continue playing. He'll need at least a couple weeks to become entirely healthy, they said.

In April, Castillo was re-signed to a one-year, $1 million deal that netted him a $175,000 signing bonus. He has missed 30 games the past six seasons to injury, including 15 games in 2011 with a season-ending tibial plateau leg fracture.

He totaled 211 tackles with 19 sacks in 82 games (79 starts) with another 22 tackles and two sacks in seven playoff games.